I don't believe there is a chip or tuner for Toyota products.
There is engine info available through the OBD-II port for mechanics to diagnose problems with the car. You can get that data lots of different ways. For example, a Bluetooth OBD-II dongle and your phone. The device you mentioned puts that info into a pretty format but that's about it.
With a special cable, your laptop and the Toyota app you can make changes to things like what the remote does (eg. Opens windows) but nothing to change performance. You can't program the shift points etc...
There is power to be made with a tune. Why? Because oem tunes are designed for emissions and durability. So minor changes to fuel ratio and spark timing can yield minor gains at the potential expensive of these attributes. Usually at higher rpm. Also because there is some variance engine to engine and a custom tune can dial in this variance. So usually minor but in combo with intake and exhaust can add up some because now you're starting to add more air, and this is really the key. Note these latter two are custom, not off the self tuner in a box.
When this really takes off is when you can significantly modify the displacement of the engine (amount of air the engine can ingest). Cam, heads, stroker, forced induction. A stage 1 tune on my '99 turbo I-4 Audi A4 went from 155hp to >200hp, with consistent gains across the rpm range. This was due to increasing boost and then matching fuel and spark to the increased effective displacement. I never dyno'd my stroker 2FE but I did tune with a programmable AFM to match fueling to the ~10% displacement bump and increased static timing using an aftermarket knock sensor to control detonation. A stage 2 on my VW R would blow the doors off.
But here we're not talking about these kinds of mods. So best case is very minor increases at the risk of undoing the hundreds of hours of calibration the factory did. Pass.
It is my understanding that turbocharged engines can have significant increases in power with a tune (by turning up the boost), but that the amount of gains is much smaller from a naturally aspirated engine.
I find that the Land Cruiser has more power than I need and I bought for it is reliability and longevity, so I'm not interested in the risk involved in a tune. YMMV.
There's many OBD-II style data/gauge displays. Little to no tuners available for the 200-series. Tuning isn't just a slider on some fuel or timing adjustment. It's a 3D map of values. With potentially many many maps overlaid to arrive at some final tuning value.
I would look at the Tundra market for potentials. Bullydog would be what you're looking for that has display and tune flashing capabilities. They have cracked the encrypted Toyota ECU, offering multiple maps for the Tundra, including supercharger maps. If we want this, we should reach out to them to express interest. Most of the hardware is the same, just minor calibration differences so they should be able to re-use most of the development spent on the Tundra and Sequoia.